Preparation of aminodithiothiazoles



United States Patent Ic 3,150,130

Patented Sept. 22, 1964 Various other aminodithiothiazoles can beprepared by 3,150,130 uslng other 2,2'-bis-thiazole disulfides and othersecond PREPARATION OF AMINODITHIOTHIAZOLES Albert F. Hardman, Akron,Ohio, assignor to The Goodyear Tire & Rubber Company, Akron, Ohio, acorpoary amines in the place of the materials used in the ex ample.Representative examples are ration of Qhio 5 2,2'-bis-thiazoledisulfide; No Drawing. Filed July 31, 1962, Ser. No. 213,6702,2-bis-4-methyl-thiazoledisulfide;

6 C aim 260-2471) 2,2'-bis-4-ethyl-thiazoledisulfide;

2,2-bis-4-n-propyl-thiazoledisulfide2,2'-bis-4-n-butyl-thiazoledisulfide;2,2-bis-4,5-dimethyl-thiazoledisulfide;2,2'-bis-4,S-diethyl-thiazoledisulfide;2,2-bis-4,5-di-n-propyl-thiazoledisulfide;2,2-bis-4,5-di-n-butyl-thiazoledisulfide2,2'-bis-4-phenyl-thiazoledisulfide;2,2'-bis-4-phenyl-5-methyl-thiazoledisulfide2,2-bis-4-phenyl-benzothiazolcdisulfide;2,2-bis-6-phenyl-benzothiazoledisulfide;2,2-bis-tetrahydrobenzothiazoledisulfide; and2,2-bis-naphtho-thiazoledisulfide.

This invention relates to aminodithiothiazoles and to a method of makingthese materials. 10

Aminodithiazoles are powerful accelerators of vulcanization of rubber.They can be used to promote the curing of rubber with or without sulfurand are particularly useful in black tread stocks and other compositionscontaining rubber in which a powerful, yet delayed action, non-scorchingaccelerator is needed to promote the curing of the rubber composition.

The compounds with which this invention is particularly concerned aresecondary aminodithiothiazoles which can be represented by the generalstructural formula i The 2,2-bis-benzothiazoledisulfide is the preferredspecies. The amines which can be used in this invention are aliphatic,cycloaliphatic and aralkyl secondary amines. R1 Representative examplesof such amines are: dimethylamine, diethylamine, di-n-propylamine,diisopropylin which R and R are the same or different aliphatic, amine,dibutylamine, dicyclohexylamine, methylethylcycloaliphatic, or aralkylgroups, or R and R together amine, methylpropylarnine,methylisopropylamine, ethylform a single chain and R is an azoleselected from the propylamine, ethylbutylamine, methylcyclohexylarnine,group consisting of Z-thiazoles and Z-aryl thiazoles. morpholine,thiomorpholine, and piperidine.

According to the invention, the aminodithiothiazoles The illustrativeexample shows the reaction of the are prepared by reacting a.2,2-bis-thiazoledisulfide with a thiazole disuhide, the amine and sulfurbeing carried secondary amine and sulfur in the presence of an inoroutin the presence of sodium carbonate. Sodium carganic alkaline material.bonate is not an essential ingredient in carrying out the The reactionappears to proceed according to the folforegoing reaction but it hasbeen found that the preslowing equation in which 2,2-bis-benzothiazoledisulfide once of an inorganic alkaline material and particularly andmorpholine are used as representative starting matethose selected fromthe carbonates, bicarbonates and rials to react with sulfur: hydroxidesof the alkali metals causes the reactants to The practice of theinvention is illustrated by the folinter-react at a faster rate andgives improved yields of lowing representative example: product.Representative examples of suitable inorganic Thirty-four grams of2,2'-bis-benzothiazole disuliide, alkaline materials which may be usedto catalyze the re- 3.5 grams of sulfur, 18 grams of morpholine and 100action between thiazole clisulfides, secondary amines and milliliters ofmethanol were placed in a small three-neck sulfur are sodium carbonate,sodium bicarbonate, sodium flask set up with a stirrer and refluxcondenser. The mixhydroxide, potassium carbonate, potassium bicarbonateture was stirred and heated under refluxing conditions. and potassiumhydroxide.

After 1 /2 hours of reaction time no crystals of the de- In preparingaminodithiothiazoles by the above dissired product had formed, whereupon6 grams of sodium closed process best results are obtained when thereaccarbonate were added to the reaction mixture. The mixtion isconducted in a suitable organic solvent. However, ture efiervesced andin 10 minutes began thickening with the reaction will proceed atreasonable rates to give a crystals. After one hour the mixture wascooled, filtered, 0 satisfactory yield of aminodithiothiazole withoutemployand washed with methanol and with water. A yield of ing solvents.Solvents which have been found to be suit- 24.5 grams of product havinga melting point of l33-l34 able for use in this process are thecustomary organic C. was obtained, this represents a yield which is 97%of solvents such as the lower aliphatic alcohols. Representatheoretical.tive examples of suitable solvents are methanol, ethanol,

From a consideration of the above example it will be isopropanol, normalpropanol, normal butanol and other apparent that even though there was asubstantial excess solvents such as benzene, toluene, and xylene. ofmorpholine employed the reaction between the disul- The reaction of theexample Was carried out at refide, morpholine and sulfur did not proceedto a satisfiuxing temperature. Higher or lower temperatures can factorydegree of completion in 1 /2 hours but that a be used. The temperatureis not critical, but it is desirvery high yield of the desiredaminodithiothiazole was able to use a temperature which will givereasonably fast obtained within a relatively short time after theintroducreaction rates so that the process can be economically tion ofsodium carbonate to the reaction mixture. arried out,

This application is a continuation-in-part of application Serial No.716,538, filed February 12, 1958 and now abandoned.

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention it will be apparent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

I claim:

1. In the process of preparing an aminodithiothiazole which comprisesreacting a 2,2'-bis-thiazole disulfide with a secondary amine andsulfur, the improvement wherein the reaction is conducted in thepresence of an inorganic alkaline material selected from the groupconsisting of the carbonates, bicarbonates and hydroxides of the alkalimetals.

2. In the process of preparing an aminodithiothiazole which comprisesreacting in an organic solvent a 2,2"-bisthiazole disulfide with asecondary amine and sulfur, the improvement wherein the reaction isconducted in the presence of an inorganic alkaline material selectedfrom the group consisting of the carbonates, bicarbonates and hydroxidesof the alkali metals.

3. In the process of preparing a Z-(amino dithio) benzothiazole whichcomprises reacting a 2,2'-bis-benzo thiazole disulfide with a secondaryamine and sulfur, the improvement wherein the reaction is conducted inthe presence of an inorganic alkali material selected from the groupconsisting of the carbonates, bicarbonates and hyroxides of the alkalimetals.

4. In the process of preparing a Z-(amino dithio) benzothiazole whichcomprises reacting a 2,2'-bis-benzothiazole disulfide with a secondaryamine and sulfur, the improvement wherein the reaction is conducted inthe presence of an alkaline material selected from the group consistingof sodium carbonate, sodium bicarbonate, sodium hydroxide, potassiumcarbonate, potassium bicarbonate, and potassium hydroxide.

5. In the process of preparing 2-(4-morpholinyldithio) benzothiazolewhich comprises reacting 2,2-bis-benzothiazoie disulfide with morpholineand sulfur, the improvement wherein the reaction is conducted in thepresence of an alkaline material selected from the group consisting ofsodium carbonate, sodium bicarbonate, sodium hydroxide, potassiumcarbonate, potassium bicarbonate, and potassium hydroxide.

6. In the process of preparing 2-(4-morpho1inyldithio) benzothiazolewhich comprises reacting 2,2-bis-benzothiazole disulfide with morpholineand sulfur, the improvement wherein the reaction is conducted in thepresence of sodium carbonate.

References Cited in the file of this patent UNITED STATES PATENTS2,837,519 Hardman June 3, 1958

1. IN THE PROCESS OF PREPARING AN AMINODITHIOTHIAZOLE WHICH COMPRISESREACTING A 2,2''-BIS-THIAZOLE DISULFIDE WITH A SECONDARY AMINE ANDSULFUR, THE IMPROVEMENT WHEREIN THE REACTION IS CONDUCTED IN THEPRESENCE OF AN INORGANIC ALKALINE MATERIAL SELECTED FROM THE GROUPCONSISTING OF THE CARBONATES, BICARBONATES AND CHYDROXIDES OF THE ALKALIMETALS.
 5. IN THE PROCESS OF PREPARING 2-(4-MORPHOLINYLDITHIO)BENZOTHIAZOLE WHICH COMPRISES REACTING 2,2''-BIS-BENZOTHIAZOLE DISULFIDEWITH MORPHOLINE AND SULFUR, THE IMPROVEMENT WHEREIN THE REACTION ISCONDUCTED IN THE PRESENCE OF AN ALKALINE MATERIAL SELECTED FROM THEGROUP CONSISTING OF SODIUM CARBONATE, SODIUM BICARBONATE, SODIUMHYDROXIDE, POTASSIUM CARBONATE, POTASSIUM BICARBONATE, AND POTASSIUMHYDROXIDE.